A fuel cell is an apparatus that converts chemical energy stored in a hydrocarbon or a hydrogen fuel to electrical energy through an electrochemical reaction with air. A polymer electrolyte fuel cell (PEFC) used in vehicles or the like is a fuel cell that uses a polymer as an electrolyte, and is operated at a temperature of not more than 100° C. Hydrogen ions produced by an anode of a fuel cell stack flows to a cathode through an electrolyte, and generates electricity while reacting with oxygen in the cathode to generate water.
Then, the fuel cell stack may be accommodated in a stack housing, and an inside and an outside of the fuel cell stack may be partitioned such that materials in the interior of the stack housing are not leaked to the outside. However, some moisture or hydrogen may be leaked to the outside of the fuel cell stack and be accommodated in the stack housing.
Further, a process of generating electricity in the fuel cell stack is a heat emitting reaction, and accordingly, moisture may be condensed in the interior of the stack housing due to a temperature difference between the inside and the outside of the stack housing.
If moisture is condensed in the interior of the stack housing, components of the fuel cell stack may be corroded. Accordingly, fuel cell systems for reducing moisture in the fuel cell stack is necessary.